Fix collection (mailer) bugs

app/views/collection_invitation_mailer/send_invitation.text.slim

@@ -1,13 +1,15 @@
 = t('collections.invitation_mailer.greeting', user: @recipient.name)
-
-= t('collections.invitation_mailer.invitation_message', collection: @collection.title)
-
-= t('collections.invitation_mailer.collaboration_details')
-
+= "\n\n"
+= t('collections.invitation_mailer.invitation_message', collection: @collection.title).html_safe
+= "\n\n"
+= t('collections.invitation_mailer.collaboration_details').html_safe
+= "\n\n"
 = t('collections.invitation_mailer.view_collection_instructions')
+= "\n\n"
 = collection_url(@collection)
-
+= "\n\n"
 = t('collections.invitation_mailer.contact_info')
-
+= "\n\n"
 = t('collections.invitation_mailer.thank_you')
+= "\n"
 = t('collections.invitation_mailer.team_signature', app_name: t('application.name'))

app/views/collections/_form.html.slim

@@ -48,7 +48,7 @@
         br
   .form-group
     .actions.btn-group role='group'
-      = button_tag type: 'submit', class: 'btn btn-important', form: 'edit_collection' do
+      = button_tag type: 'submit', class: 'btn btn-important', form: @collection.new_record? ? 'new_collection' : "edit_collection_#{@collection.id}" do
         i.fa-solid.fa-folder-open
         =< t('.button.save')
       - if @collection.tasks.present?

spec/mailers/previews/collection_invitation_mailer_preview.rb

@@ -6,6 +6,6 @@ class CollectionInvitationMailerPreview < ActionMailer::Preview
   def send_invitation
     collection = FactoryBot.build(:collection, id: 1)
     user = FactoryBot.build(:user, id: 2)
-    CollectionInvitationMailer.send_invitation(collection, user)
+    CollectionInvitationMailer.with(collection:, recipient: user).send_invitation
   end
 end